Explanation:
It is not a coincidence that planets line up.
That's because all of the
planets
orbit the
Sun in (nearly)
a single sheet called the plane of the
ecliptic.
When viewed from inside that plane -- as
Earth dwellers are likely to do --
the planets all appear confined to a
single band.
It is a coincidence, though, when
several of the brightest planets all appear in nearly the same direction.
Such a coincidence was captured just last week.
Featured above, six planets and Earth's Moon were all
imaged
together last week, just before sunset, from
Mornington Peninsula
in
Victoria,
Australia.
A second band is visible across the top of this tall image -- the central band of
our
Milky Way Galaxy.